Copyback is a process whereby data is read back from storage (such as a solid state storage, including NAND Flash) and written back to storage (e.g., at a different address or location). In the case of solid state storage systems, information is stored in the form of voltage or charge by cells. Over time, the amount of charge stored may drift outside of some preferred range, for example because additional charge is unintentionally added, or because charge leaks out as the electrical insulation of the solid state storage media breaks down. Thus, copybacks may periodically be performed to refresh the amount of charge stored. Other storage management processes may also use copybacks.
Because of some characteristics or properties that are specific to solid state storage, copybacks may occur more frequently compared to other types of storage systems, such as hard disk drive systems. It would be desirable if improved copyback techniques were developed, specifically that accelerated the copyback process.